【作者】 苏国林；

【导师】 邓景康；

【作者基本信息】 清华大学 ， 物理学， 2006， 博士

【摘要】 电子动量谱学（Electron Momentum Spectroscopy,EMS）以其能够同时测量物质中电子态的能量分布和动量分布的优势,而发展成为研究物质的电子结构和电离机制的强有力的工具,是当前物理与化学、生物、材料、医药等多学科交叉的前沿领域之一。本论文工作主要分为两个部分:用电子动量谱学对分子芯轨道及电子关联效应、扭曲波效应、化学位移等基本物理化学问题的研究和电子动量谱仪的更新换代（即数据获取系统的研制）。本论文在国际上首次利用EMS开展分子芯轨道（core orbitals）化学位移研究。N2O分子两个N1s芯轨道的结合能为四百多电子伏特,（e,2e）反应微分散射截面比价壳层轨道低三个量级。通过对N₂O分子两个N1s芯轨道的EMS研究,得到了比化学分析用电子能谱（Electron Spectroscopy for Chemical Analysis,ESCA）更加丰富和深刻的化学位移信息。ESCA方法通过研究不同化学环境中分子芯轨道结合能的差异给出化学位移的信息,而EMS方法不仅可以给出芯轨道结合能的差别,还可以得到波函数的差异,而波函数是量子力学和量子化学最关心的信息。另外,通过对N₂O分子芯轨道的EMS研究,检验了分子芯轨道层次的电子动量谱学理论和量子化学理论方法。论文还通过对药物分子C₄H₆O₂、N₂O和氟利昂分子CH₂F₂、CHF₂Cl价壳层轨道的EMS研究,不仅得到了它们电子结构的信息,还研究了电子关联效应、扭曲波效应、分子轨道排序和量子化学计算方法等基本的物理化学问题。论文最后还介绍了基于通用串行总线（Universal Serial Bus,USB）的多参数数据获取系统。硬件系统通用性强、使用灵活、调试方便;软件系统是利用Visual Basic和Visual C++混合编程,总共包括八千多行程序。它除了界面友好、程序可读性好和效率高以外,在设计上还采用了简洁而完备的控制算法、谱构造算法和离线数据处理算法。另外,软件系统中还嵌入自动报警功能,为保证数据采集的准确性和提高实验效率起了很大作用。更多还原

【Abstract】 Electron momentum spectroscopy (EMS), which could give both of the electron binding energies and the electron momentum density distributions at the same time, has been developed to be a powerful tool for the investigation of electronic structure and electron ionization mechanics and become one of the leading fields of physics, chemistry, biology, material and pharmaceutical sciences.The work of the dissertation could be divided into two parts. One is the EMS study of molecular core orbitals and some fundamental chemical physics issues and the other is the development of the data acquisition system.The EMS measurement of the chemical shift is reported for the first time. By studying the N1s core orbitals of N2O which are of more than 400 eV binding energies and three orders of magnitude lower than the valence orbitals in the (e, 2e) cross-sections, the EMS theory of core orbitals is evaluated and a more direct and pronounced manifestation of the chemical shift than Electron Spectroscopy for Chemical Analysis (ESCA) is also demonstrated. ESCA gives the information of the chemical shift and chemical environment only by the differences of binding energies, however, EMS could deliver the information by both of the differences in binding energies and wavefunctions, the heart and soul of physics and quantum chemistry.The dissertation also presents the EMS study of the complete valence orbitals of the pharmaceutical molecules and Freon molecules. The electron structures of these molecules are obtained. Furthermore, we get a lot of valuable results in some fundamental chemical physics issues, such as electron correlation effects, distorted wave effects, orbital ordering and evaluation of the quantum chemistry calculation methods and so on.The dissertation also gives a detailed description of the data acquisition system. The hardware of the system is based on USB interface and thesoftware, including more than 8,000 lines, is developed with the Visual Basic and Visual C++ language. The software system has a friendly interface as well as good readability and high efficiency. Furthermore, it has a brief and complete algorithm design on auto-controlling, spectrum displaying and off-line data analyzing. Moreover, the auto alarm function is embedded in the software, which greatly increases the reliability and efficiency of the experimental data.更多还原